Using the Time Calculator
Enter the first duration in its separate hour, minute and second fields. The second duration is entered entirely in seconds, so one hour is 3,600. The tool converts the first duration to seconds before applying the selected operation.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- First duration: hours
- 2
- First duration: minutes
- 30
- First duration: seconds
- 0
- Operation
- Add
- Second duration (seconds)
- 3600
Example result
- Total seconds
- 12,600
- Duration
- 3h 30m 0s
Method and assumptions
Converts each duration to seconds, performs the operation, and converts back.
Write durations in a consistent format
Hours, minutes and seconds use base-sixty subdivisions, while decimal hours use fractions of an hour. Convert to one common unit before combining values from different sources. Keep the sign with the entire duration after subtraction. A duration can exceed a day without representing a specific date or local clock time.
Common question
What does a negative duration mean?
It means the duration you subtracted is larger than the starting duration. The minus sign applies to the whole result. It does not represent a clock time before midnight or a change of timezone.
Guide updated .